The PLG100-XG card can only be used for sequencing. It's a 32 voice, 16 part XG synth that responds on it's own MIDI port (thanks to some Yamaha MIDI magic).
Each PLG boards adds a complete synthesizers that can be played alone or layered with CS6x sounds:
PG150-AN 5 voice VA (uses AN1x engine)
PLG150-DX 16 voice DX7-II synth
PG150-DR 32 voices of sampled drums
PLG150-PC 32 voices of sampled percussion
PLG150-PF 32 voices of various sampled piano, organ, clavinet sounds
PLG150-AP 64 voices of one high-grade sampled Yamaha acoustic piano
PLG150-VL monophonic physical modeling synth (based on VL-70 engine)
PLG100-VH effects processor does harmonies, pitch shifting, pseudo-vocoding
There's also the rare Japan-only PLG100-SG formant synthesizer
; uses FS1R technology to create "singing voices". A real weird one!!!
There is no way to get CS1x/CS2x sounds into a CS6x, period.
If you are looking for more CS6x sounds, a few places to try:Easysounds
third party patch developerJayB's Patches
(video demo with link to free patch set)CS6X Yahoo Group
(appears to be inactive but has downloads)
I listened to Hatfield and the North at Rainbow. They were very wonderful and they made my heart a prisoner.